The study of chemistry in aqueous micelles has taken on twofold importance as a tool for understanding a range of physiological chemistry. In-vivo aggregation of surfacant-like molecules (bile salts, gangliosides, phospholipids and glycolipids) has been implicated as critical to the mode of action in a variety of receptors as well as digestive and transport functions. Secondly, micelles have been viewed as a simplified model for the crucial interactions in enzyme-substrate and hormone-receptor complexes. While some broad principles of the effect of a micellar environment on chemical behavior have been delineated, little is known about the ability of oriented, hydrophobic media to perturb chemical reactivity and selectivity. Therefore, we propose a study of these interactions, using as probes systems whose basic chemistry is well understood. We suggest that this environment will have a profound effect on binding specificty, chemical reactivity and selectivity, and on both inter- and intramolecular cooperativity. In some of the systems to be studied, the micellar environment could control selection between prochiral faces of a substrate based on the cooperative action of surfactant head groups. A different approach will allow the hydrophobic region of the micelle to protect portions of a substrate while enhancing reaction elsewhere in the same molecule. We have also designed systems which give a fundamental calibration of the ability of the interfacial medium to affect reaction site specificity as well as nucleophilicity and basicity of bound ions and the balance between inter- and intramolecular processes. These systems are based on well precedented chemistry and their analysis involves a range of analytical techniques and organic chemistry. We envision this approach as a first step towards ultimately applying chemical probes to other interfacial environments of greater complexity.